This invention relates to plastic bottles for sterile liquids.
A large variety of bottles and related closure systems have been proposed. One such is that described in GB Pat. No. 2080775. In this a closure element, which is separately formed from the bottle, is heat sealed onto the neck of the bottle. The line where the closure is sealed onto the bottle is weaker than the rest of the bottle so that the closure can be broken off. This is achieved by having a jacking ring comprising fingers which snap into a recess above the heat seal and as the jacking ring is unscrewed upwards the cover is removed.
In another type of bottle shown in EP 50490 a cover is formed over the neck during the moulding operation. The threaded neck has an annular portion above the thread. During the moulding operation a V-shaped groove is formed in the annular portion to provide a frangible section. The bottle carries a cap, and is opened by screwing the cap downwards thereby breaking the frangible portion. A ring inside the upper part of the cap then locates inside an annular groove in the cover so that on unscrewing the cap, the sheared-off cover can be removed from the neck.